Previous experiments with mice had suggested that Muller glia cells, a type of metabolic cell that crosses the retina, play an essential role in guiding and focusing light scattered throughout the retina.

To test this, Ribak and his colleagues ran computer simulations and in-vitro experiments in a mouse model to determine whether colours would be concentrated in these metabolic cells.

They then used confocal microscopy to produce three-dimensional views of the retinal tissue, and found that the cells were indeed concentrating light into the photoreceptors.

“For the first time, we’ve explained why the retina is built backwards, with the neurons in front of the photoreceptors, rather than behind them,” Ribak said.